Question

Which of the following is the correct electronic configuration for oxygen according to Hund's rule?

• A. $1s^{2}2s^{2}2p_x^{2}2p_y^{1}2p_z^1$
• B. $1s^{2}2s^{2}2p_x^{2}2p_y^{2}2p_z^0$
• C. $1s^{2}2s^{1}2p_x^{2}2p_y^{1}2p_z^2$
• D. $1s^{1}2s^{2}2p_x^{2}2p_y^{2}2p_z^1$

Answer 1

The correct option is A $1s^{2}2s^{2}2p_x^{2}2p_y^{1}2p_z^1$

Hund's rule states that pairing of electrons in the orbitals belonging to the same subshell does not take place until each orbital belonging to that subshell has one electron each.
In option (a), Hund's rule is satisfied whereas in other options either Hund's rule or Aufbau principle is violated.